Stuffed bird house

That active bird house from earlier this month? We are not exactly sure what has happened to it: we have not seen any birds in or near it for the past week, and what is even more bizarre is that the birds appear to have stuffed the house with items normally used for building a nest:

We doubt that there is a nest inside, otherwise we would have observed more activity around the house. In fact, we are not sure if any birds can get into the structure anymore (or at least Blue Tit-sized birds anyway, as they were the ones using it before).